August 26, 2009 at 2:17 pm by Capitol Avenue Club under Atlanta Braves, Defense, Pitching, Statistical Analysis, Transactions
In the year 1969, two pitchers played for two different teams. Pitcher A went 14-11 with a 3.24 ERA and pitched 211 innings. His club made the post-season. Pitcher B went 12-16 with a 4.67 ERA and pitched 208 and 1/3 innings. His club also made the post-season.
The next year, 1970, neither pitcher pitched for their previous club and they both pitched for the same (new) team. Pitcher A, the one with the winning record and the sub-3.5 ERA, posted a 4.48 ERA with their new club. Pitcher B, the one who had a losing record and an ERA over 4.5, posted a 3.14 ERA.
Sample size? No.
There are a number of things that contributed to the seemingly unexplainable improvement of pitcher B and the regression of pitcher A. First of all, pitcher B was rather unlucky. The difference between his 3.81 FIP and his 4.67 ERA, -0.86, ranked 3rd in the league. While pitcher A was right at his level. It makes sense. Pitcher B struck out 200 and walked only 61. In most cases, you’re going to post an ERA better than 4.67 with those peripherals. His home run rate was slightly elevated due to a bad pitchers’ park and the defense behind him was worse than bad. In 1969.
Pitcher A had the luxury of playing in a very pitcher-friendly ballpark with one of the most talented defenses in the league behind him. He didn’t have any of the bad luck pitcher B had. As a result, his 3.23 FIP was right at his 3.24 ERA. Despite his solid yet uninspiring 147-to-45 strikeout-to-walk ratio.
Neither pitcher faced a DH in 1970. Pitcher B did in 1969, pitcher A did not.
Based on those factors, you’d expect pitcher B to improve moving to a neutral park with a neutral defense. You’d also expect pitcher A to regress. And that’s what happened in 1970.
This would be a true story if I changed 1969 to 2008, 1970 to 2009, pitcher A to Derek Lowe, and pitcher B to Javier Vazquez. It’s obviously not this simple, but you get the idea. It wasn’t that hard to see this coming, folks.